The present inventive concept relates to methods of fabricating semiconductor devices. More particularly, the inventive concept relates to methods of fabricating nonvolatile, phase-change semiconductor memory devices.
Semiconductor memory devices may be generally categorized as volatile devices that lose stored data in the absence of applied power and nonvolatile devices that retain stored data when applied power is interrupted or discontinued. Among other types of nonvolatile memory devices, flash memory has been widely used in many commercial applications due to its high memory cell integration density and readily fabricated stacked gate structure. However, so-called phase change memory devices are now being considered as a possible replacement for flash memory in certain applications.
However, there are a number of challenges to the efficient and reliable fabrication of phase-change memory devices. For example, like other semiconductor memory types, a phase-change semiconductor memory includes a dense array of individual memory cells. Each phase-change memory cell is configured around a small portion of phase change material that has been patterned from one or more constituent material layer(s). A mold layer (or combination of mold layers) is commonly used during methods of fabricating phase-change memory devices to separately form (or pattern), on a unit memory cell basis, respective nodes of phase-change material. However, when separating phase change material patterns on a unit memory cell basis, the mold layer defining the phase change material patterns or phase change material patterns may become damaged.